In recent years long-format images wherein a plurality of x-ray images is captured and concatenated together to obtain a single x-ray image have become widely popular as a method for imaging locations (such as the entire spinal column or the entire leg) that are larger than the detecting surface in the x-ray equipment (See Japanese Unexamined Patent Application Publication 2004-358254, Japanese Unexamined Patent Application Publication 2007-135692 and Japanese Unexamined Patent Application Publication 2007-185209).
In long-format radiography, first an imaging distance between the subject and the x-ray tube is kept constant, the long-format imaging region is determined, and then each individual imaging region is determined through partitioning into regions that fit into the detector field of the x-ray detector. Partitioning into individual imaging regions is performed so that adjacent imaging regions overlap. Moreover, shifting the partitioned imaging region with each imaging cycle makes it possible to obtain a plurality of concatenated x-ray images. A single x-ray image is obtained through image processing on the regions wherein there are overlapping x-ray images, to concatenate them together.
However, this type of long-format radiography has problems such as the following. In x-ray radiography, when imaging a long-format imaging region continuously, there will be variability in the image quality, such as in the consistency within the area that is imaged, so that when image processing is performed to overlap adjacent x-ray images, the image quality of the overlapping imaged areas will suffer, making the image difficult to read. For example, when performing long-format imaging with the entirety of the lower extremities, as the imaging region, in a state wherein there is a load on the knees in order to perform a radiographic examination focusing on the knee joint portion along with understanding and the lower extremities as a whole, if the overlapping image area is at the knee joint portion that is the location of interest in the examination, then it will be necessary to perform the radiological examination of the hip joint portion using an x-ray image that has reduced quality. Moreover, because the overlapping image area in adjacent images in the long-format imaging region is imaged twice, this can lead to increased impact on those locations that should be protected from x-rays (such as the reproductive system). Given this reasoning, it is desirable to eliminate from the overlapping image areas in adjacent images locations of interest, such as the locations one wishes to examine, locations for which one wishes to minimize the x-ray exposure, and the like. Sometimes the x-ray radiography must be performed again if the location of interest is in the overlapping image area. Because of this, it is desirable to protect the patients from excessive x-ray exposure in advance.
The present invention was created in contemplation of such circumstances, and the object thereof is to provide an x-ray radiography device wherein it is possible to confirm accurately, prior to the x-ray radiography, whether or not the overlapping image area in adjacent imaging regions is not provided at a location of interest of the examination subject.